Compasses.



0. TROM'L I'TK UUMPASSES.

APPLICATION FILED JULY 19. 1913.

1,098,536; Patented June 2, 1914.

UNITED STATES PATENT OFFICE.

OSCAR TROM-LITZ, 0F CLEVELAND, OHIO.

COMPASSES.

To all whom it may concern:

Be it known that I, OsoAn TnoMLITz, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain. new and useful Improvements in Compasses, of which the following is a specification.

This invention relates to compasses, or instruments of similar type, and has for its object to provide an improved construction of the legs of the instrument, whereby they will be held at desired adjustment without the use of screws or other devices.

The construction is such that the main parts of the instrument may be readily stumped or made from sheet metal, at a low cost, each leg consisting of a plurality of strips or sheet metal members which when clamped together will give extensive friction binding surfaces, which will hold the legs in position.

A further object of the invention is to provide improved means for quickly adjusting one of the leg members so thata succession of curves of different diameters may be successively described in a short time, with out changing the main adjustment of the legs.

The invention is illustrated in the accompanying drawing in which Figure l is a side view of he instrument. Fig. 2 is an edge view thereof. Fig. 3 is a detail in section.

Referring to the drawings 6 indicates a forked head piece between the branches of which the upper ends of the legs are held. The upper part of each leg consists of a. plurality of similar strips or plates 7, of which three will ordinarily be sufficient, the upper ends of these strips being fitted one between the other where they are held between the branches of the head by the screw or rivet 8, in friction tight contact with each other. The lower member of one leg comprises a plurality of strips 9, of sheet metal, the upper ends of which fit between the lower ends of the strips 7 where they are connected by the pivot screw or rivet 10, forming a friction joint. One of the strips 9 has, near the lower end thereof, and at its inner edge, an inwardly oflset flange 11, which serves to form a guide or retaining flange for the lead or marker 12, which is clamped between the lower ends of the strips by a thumb screw 13, extending through the strips. The other leg of the compasses com- Specification of Letters Patent.

Application filed July 19, 1913.

Patented June 2, 1914. Serial No. 779,927.

prises a piece or plate 14 the upper end of which is slotted or divided by a kerf to form a plurality of parts 15 which fit between the lower ends of the members 7, a frlction joint being formed by the screw or rivet 16. The piece 14 is pivotally connected by a screw or rivet 17 to a plurality of strips 18, between the upper ends of which plate 14 is held. and between the lower ends of which the centering point, 19, or the like, is clamped by a thumb screw 20. The lower end of the plate 14 is recessed on its inner edge, below the pivot 17, and the strips 18 have openings 21 opposite said recess. A thumb screw 22 is tapped into the lower end of the plate 14 with its head 23 fitting in said recesses 21.

This screw serves for fine adjustment, or for quickly changing adjustment of the legs, as in making a succession of concentric circles close together. By turning the screw 22 the head thereof, bearing against the slight projections 24 at the opposite sides of the recesses 21, will swing the leg members 18 ac cordingly. The threaded stem of the screw 22 passes between the upper ends of the strips 18, and into the tapped hole formed in the plate 14 to receive it.

The members 7, 9 and 18 of the legs can be readily stamped from thin sheet metal, and when assembled in the manner described produce multiple friction surfaces at the joints, which will not slip except by special effort. The plurality of strips also gives a desirable stiffness to the legs.

I claim:

1. In compasses or the like, a forked head piece, and legs each comprising upper and lower members, each member consisting of a plurality of strips, the ends of the strips of one member being pivotally clamped between the ends of the strip of the other member at the joints, and the upper ends of the strips of the upper members being pivotally clamped together between each other and between the forks of the head piece.

2. Compasses having a leg consisting of an upper member, a lower member, a connecting plate pivoted to both of said members, and an adjusting screw between the plate and one of said members, to vary their angle to each other.

3. Compasses having a leg consistin of an upper member formed of a plurality of strips, a lower member, a connectin plate pivoted to the lower member and aving member being slotted adjacent the end of said plate, and an adjusting screw the head of which fits in said slots and the stem of 15 which extends between the strips and bears against the plate.

In testlmony whereof, I aflix my signature in presence of two witnesses.

OSCAR TROMLITZ.

Witnesses:

EDITH L. SMITH, C. W. FOWLER. 

